DE69629901T2 - DEVICE AND METHOD FOR INSULATING AND TESTING A FORMATION - Google Patents

Description

This invention relates to an apparatus and a method for checking background formations and storage.

When drilling a borehole for commercial Development of hydrocarbon reserves is encountered in numerous underground storage layers and formations. To about the Formations to find out information, such as whether the Storage layer containing hydrocarbons, recorders have been included in drill strings, to evaluate several properties of these storage layers. you has systems that measure while they drill (hereinafter MWB), developed the specific resistance and nuclear recorders containing some of these Characteristics during the execution continuously monitor the hole can. The MWB systems can Generate data on the presence of hydrocarbon, saturation level and porosity data belong. Furthermore telemetry systems have been developed for use with MWB systems, to the data to the surface to transmit. A common one Telemetry is the pulsed drilling fluid system, one of which Example can be found in U.S. Patent 4,733,233. An advantage of one MWB-Systems is the real-time analysis of underground storage for another commercial exploitation.

U.S. Patent 5,233,866 describes a test fixture and a method of the generic types for accurate and fast Measuring formation pressure and permeability in oil and gas generating formations, especially in formations with low or high permeability. The testing device can be transported on a drill string or on a cable. Usually it is used as a component of a wired tester used. The testing device has an extended subassembly as part and package of the combination for the Pull down or a formation pressure tester that connects the flow line of the drill bit is directly assigned. By putting on a very slow rate of pressure drop in the drill pipe flow line can formation pressure and formation permeability can be determined quickly, generally during the first minute of testing. With high permeability and soft formations, the formation pressure is also determined if the seal during of the flow period get lost. Corrections can be made in formations with low permeability for the overload effect be made when using the collected data. For determination formation pressure, formation permeability, overcharge and drilling fluid cake properties a simple mathematical model can be used from the data obtained become.

U.S. Patent 4,635,717 describes a method and apparatus for use on a recording wire cable for the Sampling and testing well fluids, those obtained from such testing Surface results transferred for determination whether the specific sample to be tested is collected and to the surface to be brought or not. The device has one in the borehole located tool with an inflatable double packer for insulation an interval of the borehole connected to a hydraulic pump, the pump being used in turn to make the double packer distend and an interval of the wellbore to isolate and remove fluids from the isolated interval to test chamber facilities remove where the resistivity, the redox potential (Eh) and the acidity (pH) is determined to be final selected Samples to one or more sample container chambers in the drill bit attached or returned to the borehole if not selected.

The commercial development of Hydrocarbon fields require significant amounts of capital. Before a development of the field begins, the operators want so many Dates as possible have to refer to the reservoir commercial viability to rate. Despite the advantages of data collection during the Drilling using MWB systems often requires to conduct a further investigation of the hydrocarbon reservoirs additional To get data. That is why the hydrocarbon zones become drilling the borehole often by means of other test equipment.

To some kind of after drilling conducted Heard tests generating fluid from the storage, collecting samples, completing of the borehole and allowing pressure build-up to a static one Level. This sequence can be repeated several times in several different ways Save can be repeated within a given borehole. This type of test is known as a pressure build-up test. One of the essential ones Aspects of during Data collected from such a test is the pressure build information, which are collected after the pressure is reduced. From this data can Information regarding of permeability and the size of the memory be derived. You also need current samples of the storage fluid received, and these samples need to be checked to collect pressure-volume-temperature data necessary for hydrocarbon distribution of the memory are relevant.

To perform these important tests, it is currently necessary to pull the drill string out of the borehole. Another tool, designed for testing, is then inserted into the borehole. A cable is often used to get the testing tool into the borehole to lower. The test tool sometimes uses packers to isolate the memory. Numerous communication devices have been constructed which provide for the handling of the test arrangement or alternatively for the data transmission from the test arrangement. Some of these designs include signaling with pressure pulses from the surface of the earth through the fluid in the borehole to or from or in association with the downhole microprocessor or in association with the test arrangement. Alternatively, a cable can be lowered from the surface into a landing box located in a test arrangement, whereby electrical signal communication is established between the surface and the test arrangement. Regardless of the type of tester currently used and regardless of the type of communication system used, the amount of time and money required to pull the drill string and insert a second tester into the hole is significant. If the hole deviates significantly, a cable can no longer be used to perform the test because the test tool cannot penetrate deep enough to achieve the desired formation.

There is another type of Problem related to borehole pressure conditions the while of drilling can occur. you calculates the density of the drilling fluid by a maximum drilling efficiency to achieve while the Security is maintained, the density of the desired Relationship between the weight of the column of drilling fluid and the borehole pressure, that you meet depends on. As different formations of drilling are penetrated, downhole pressure can change significantly. With the present available Equipment there there is no way accurately record the formation pressure when the drilling tool Formation penetrates. The formation pressure may be lower than expected be, which enables a reduction in the drilling fluid density, or the formation pressure may be higher than expected what may be also leads to a pressure kick. Because this information for not readily available to the operator As a result, the borehole fluid may be too high or too low too low density for maximum efficiency and maximum safety become.

There is therefore a need for a process and an apparatus for pressure testing and fluid sampling enable potential hydrocarbon reservoirs once the borehole is in the storage has been drilled without the drill string being removed becomes. There is also a need for a Method and apparatus for adjusting well fluid density responsive to changes allow in downhole pressure, to achieve maximum drilling efficiency. Finally there is a need for a Method and apparatus for blowing out the borehole prevent to favor drilling security.

It will be a formation test procedure and a formation tester disclosed. The testing device is on a work string for use in a fluid-filled borehole appropriate. The work string can be a conventional screwed, tubular drill string or be a coiled riser. It can be a work string the for drilling, reintroduction or revision applications is designed. As is required with many of these applications, must the work string will be able to work well in or holes even going horizontally. To achieve the purpose of the present Invention fully operational therefore, the work string must be able to be instead to be lowered like a cable, to be forced into the hole. The work string can be a measurement and drilling system drill bit or contain other work items. The formation tester has at least one expandable packer or other expandable Construction that for the contact with the wall of the borehole is expanded or extended can, devices for moving a fluid, for example a Pump, for the inclusion of formation fluid and at least one sensor for Measure a property of the fluid. The tester also contains Control devices for controlling various valves or pumps, which are used to control the fluid flow. The sensors and other instrumentation and control equipment must be carried by the drill bit. The drill bit must have a communication system that operates in the Able to surface with communicate while Telemetric data on the surface or in a well storage for later Pull out can be saved.

The process includes drilling a well or re-inserting it and selecting a suitable underground storage facility. The pressure or some other property of the fluid in the borehole on the reservoir can then be measured. The extendable member, such as a packer or test probe, is placed against the wall of the borehole to isolate a portion of the borehole or at least a portion of the borehole wall. When two packers are used, this creates an upper annulus, a lower annulus and an intermediate annulus in the wellbore. The intermediate annulus corresponds to the isolated part of the borehole and is positioned on the reservoir to be examined. Next, the pressure or other property in the intermediate annulus is measured. The borehole fluid, primarily drilling fluid, can then be withdrawn from the intermediate annulus with the pump. The level at which the pressure is in the middle gray stabilized, can then be measured. It corresponds to the formation pressure.

Alternatively, a piston or a other test probe from the test fixture extended to be in a sealing relationship with the borehole wall to kick, or it can be any other expandable element extended to create a zone from which substantially untouched formation fluid can be deducted. This can also be achieved by using a Positioning arm or rib from one side of the test tool is extended to the opposite side of the test tool to press into contact with the borehole wall, creating a sample channel exposed to the formation fluid. Regardless of the device used the goal is to create a zone of pristine formation fluid, from which a sample can be taken or in the properties of the fluid can be measured. This can be achieved through various facilities. The first mentioned Example is to use inflatable packers to get one isolate vertical section of the entire borehole, after which Drilling fluid is withdrawn from the isolated section until it joins with Formation fluid fills. The other examples listed achieve the goal by having an item against a stain is expanded on the borehole wall, making the formation direct contacted and drilling fluid is removed.

Regardless of the device used it must be built in such a way that it primary Operations is protected for the the work string is provided, for example drilling, the Reintroduce or revising. If an expandable probe is used, it can extend into the Pull back the drill bit or can be protected by adjacent stabilizers, or both. On Packers or other expandable elastomeric elements can be used in a recess in the drill bit or can be pulled through a sleeve or some other type of cover.

In addition to the pressure sensor mentioned above can the formation tester a specific resistance sensor to measure the specific Well fluid and formation fluid resistance or others Types of sensors included. The specific resistance of the drilling fluid differs considerably the resistivity of the formation fluid. If two packers can be used, the specific resistance of the intermediate annulus pumped fluid monitored to determine when all of the drilling fluid is out of the intermediate annulus is withdrawn. When the current from the isolated formation in the Intermediate annulus introduced is the specific resistance of the from the intermediate annulus pumped fluid monitored. If the specific resistance of the emerging fluid is sufficient differs from the resistivity of the borehole fluid it is assumed that the formation fluid has filled the intermediate annulus and the influx has ended. This can also be used determine a suitable seal for the packers, as there is a leak of drilling fluid past the packers would cause resistivity to maintain at the level of the drilling fluid.

After including the Formation can monitor the pressure in the intermediate annulus become. Pumping can also be resumed to provide formation fluid subtract from the intermediate annulus with a measured throughput. Pumping formation fluid and measuring pressure can be like required sequence to provide data that can be used to Calculate properties of the formation, such as permeability and the size. If direct contact with the borehole wall is used instead Isolating the vertical section of the borehole can be similar Investigations carried out through it be that test chambers into the test fixture are included. The test chambers can to atmospheric pressure be held while the work string is drilled or lowered into the borehole. If the extendable element has been placed in contact with the formation , a test channel being exposed to the formation fluid a test chamber be selectively brought into fluid communication with the test channel. There the formation fluid is at a much higher pressure than atmospheric pressure is flowing the formation fluid into the test chamber. That way you can several test chambers used to perform different pressure tests or To take fluid samples.

In some implementations that use two expandable packers, a drilling fluid return flow channel is included in the formation tester to allow the drilling fluid to flow back from the lower annulus to the upper annulus. Also included is at least one pump, which may be a Venturi pump or other suitable type of pump to prevent excessive pressure build-up in the intermediate annulus. Too much pressure build-up can be undesirable because the packer seal can be lost or because the actuation of expandable elements operated by differential pressure between the inner bore of the work string and the ring can be affected. To prevent excessive pressure from being generated, drilling fluid is pumped down the inner bore of the work string past the lower end of the work string (which is usually the drill bit) and the ring up. Then the fluid flows through a backflow channel and through the venturi pump passed, creating a low pressure zone on the Venturi tube so that the fluid in the intermediate ring is maintained at a lower pressure than the fluid in the backflow channel.

The device can also have a circulation valve for opening and opening Conclude the inner bore of the work string. In the work line may be provided a cross valve that the functionally Circulating valve is assigned to flow from the inner bore to allow the work string to the annulus around the work string when the circulation valve is closed. These valves can be in Operation of the tester used as means for preventing blowout become.

In the case where an inflow of Reservoir fluids penetrate the borehole, sometimes referred to as a "kick" the process has the steps of expandable packers to put and then the circulation valve in the closed position bring to. The packers are placed in a position that is above the Inflow zone is located so that the inflow zone is isolated. Next up the cross valve is brought into the open position. Then you can Drilling fluid additives are added, reducing the density of the drilling fluid elevated becomes. The heavier drilling fluid circulates through the cross valve in the work line and fills it Ring. Once the circulation of the denser drilling fluid is completed the packer can be loosened and the circulation valve opened. Then drilling can be started again.

To an advantage of the present Invention belongs the use of sensors for the pressure and resistivity with the MWB system in order the real-time data transmission to enable these measurements. Another advantage is that the present invention obtaining static prints, print builds and print removals with the work string, for example the drill string, made possible on site. A calculation of permeability and other storage parameters based on the pressure measurements can be achieved without pulling the drill string.

The packers can be placed multiple times so that testing multiple zones possible is. By measuring downhole conditions in real time possible is, can optimal drilling fluid conditions to be determined for well cleaning, drilling security and contribute to the drilling speed. When an inflow of fluid and Gas entering the well from the reservoir is high Pressure in the lower part of the borehole, which increases the risk considerably reduces that you're exposed to these prints on the surface. By completing the Borehole immediately above The critical zone is the volume of inflow into the borehole considerably reduced.

The new features of this invention and the invention itself can best be seen from the accompanying Understand drawings together with the following description, wherein same reference numerals for same parts and in which

1 4 is a partial sectional view of the device of the present invention as used with a floating well,

2 Figure 3 is a perspective view of an embodiment of the present invention with expandable packers,

3 a sectional view of the embodiment of the present invention of 2 is

4 a sectional view of the in 3 shown embodiment by adding a sample chamber,

5 a sectional view of the in 3 is shown embodiment, the flow path of the drilling fluid is shown,

6 FIG. 3 is a sectional view of a circulation valve and a cross valve included in the in FIG 3 shown embodiment can be included,

7 FIG. 4 is a sectional view of another embodiment of the present invention, showing the use of a centrifugal pump to empty the intermediate ring, and FIG

8th schematically shows the control system and the communication system that can be used in the present invention.

In 1 is a typical derrick 2 with an outgoing borehole 4 shown how this is generally known. The derrick 2 has a work string 6 , which is a drill string in the embodiment shown. On the work string 6 is a drill bit 8th for drilling the borehole 4 attached. The present invention is also applicable to other types of work lines and can be used together with a connected riser pipe as well as with a coiled stand pipe or another work line with a small diameter, for example an extension pipe. 1 shows the derrick 2 on a drilling vessel S with a riser pipe that extends from the drilling vessel S to the seabed F.

If applicable, the work string can 6 a downhole drill motor 10 to have. In the drill string 6 is over the drill bit 8th a drilling fluid pulse telemetry system 12 included that at least one sensor 14 , for example a nuclear recording instrument. The sensors 14 detect the borehole properties in the borehole, on the bit and on the storage layer, such sensors being known per se. The bottom hole assembly further has a formation tester 16 of the present invention, which is described in detail below. As can be seen, the borehole 4 one or more underground storage layers 18 intersected.

2 shows an embodiment of the formation testing device 16 in perspective view with the expandable packers 24 . 26 , in the Recesses are drawn in the body of the tool. Furthermore, between the packers 24 . 26 stabilizer fins 20 shown, which are arranged around the circumference of the tool and extend radially outwards. Furthermore, the inlet channels are to several drilling fluid return flow channels 36 and a downward channel 41 shown what is described in detail below.

In 3 is an embodiment of the formation tester 16 shown that are adjacent to the storage layer 18 is arranged. The testing device 16 has an upper expandable packer 24 and a lower expandable packer 26 for sealing engagement with the wall of the borehole 4 , The packers 24 . 26 are expandable by known means. Inflatable packer devices are known, the inflation being achieved by injecting pressure fluid into the packer. Covers may also be optionally provided for the expandable packer elements to shield them from deleterious effects during downhole rotation, collision with the borehole wall, and other forces encountered during drilling by other work performed by the drill string ,

Between the inner longitudinal bore 7 and an expansion element control valve 30 is a high pressure drilling fluid channel 27 educated. An inflation fluid channel 28 directs fluid from the first channel of the control valve 30 to the packers 24 . 26 , The inflation fluid channel 28 branches into a first branch 28A with the inflatable packer 26 is connected, and into a second branch 28B from the one with the inflatable packer 24 connected is. With a fluid channel 29 leading to a cylinder 35 leads that in the body of the test tool 16 is formed, is a second channel of the control valve 30 connected. A third channel of the control valve 30 is with a low pressure duct 31 connected to one of the backflow channels 36 leads. Alternatively, the low pressure duct 31 to a venturi pump 38 or to a centrifugal pump 53 lead, which is discussed further below. The control valve 30 and the other controls discussed are downhole by an electronic control system 100 as shown in FIG 8th to see, actuatable, which will be explained in detail later.

You can see that the control valve 30 can optionally be positioned so that it is the cylinder 35 or the packers 24 . 26 pressurized with high pressure drilling fluid that in the longitudinal bore 7 flows. This can be the piston 45 or the packers 24 . 26 for expansion in contact with the borehole wall 4 to lead. Once this expansion is reached, the control valve can be repositioned 30 lock the extended element in place. You can also see that the control valve 30 can be selectively positioned so that the cylinder 35 or the packers 24 . 26 in fluid communication with a low pressure duct, such as the backflow duct 36 , can be brought. If spring return devices in the cylinder 35 or in the packers 24 . 26 used, as is known in the prior art, the piston pulls 45 in the cylinder 35 and pull the packers 24 . 26 in their respective recesses. Alternatively, as shown below using 4 is explained, the low pressure channel 31 with a suction device, for example a pump, connected to the piston 45 in the cylinder 35 or the packers 24 . 26 withdraw into their recesses.

If the inflatable packer 24 . 26 are inflated, become an upper annulus 24 , an intermediate annulus 33 and a lower annulus 34 educated. This is more evident in 5 to see. The bloated packers 24 . 26 separate part of the borehole 4 adjacent to the storage layer 18 that is to be examined. If the packers 24 . 26 once against the wall of the borehole 4 can set an exact volume within the intermediate annulus 33 be calculated, which is useful in the pressure test methods.

The testing device 16 also includes at least one fluid sensor system 46 for recording properties of the various fluids occurring. The sensor system 46 can have a specific resistance sensor for determining the specific resistance of the fluid. A dielectric sensor for detecting the dielectric properties of the fluid and a pressure sensor for detecting the fluid pressure can also be closed. There is also a series of channels 40A . 40B . 40C and 40D intended to accomplish various goals, such as drawing an original formation fluid sample through the piston 45 directing the fluid to a sensor 46 and returning the fluid to the return flow channel 36 , Through the piston 45 goes from its outer surface 47 to a side channel 49 a sample fluid channel 40A therethrough. On the outside surface 47 of the piston 45 a sealing element can be provided to ensure that the sample is original formation fluid. This separates a portion of the borehole from the drilling fluid or other contaminants or pressure sources.

If the piston 45 The piston side channel comes out of the tool 49 aligned with the side channel 51 in the cylinder 35 , A pump inlet duct 40B connects the cylinder side channel 51 with the inlet of a pump 53 , The pump 53 can be a centrifugal pump driven by a turbine wheel 55 or is driven by another suitable drive device. The turbine wheel 55 can from a stream through a bypass channel 84 between the longitudinal bore 7 and the backflow channel 36 are driven. Alternatively, the pump 53 any other type of suitable pump. Between the outlet of the pump 53 and the sensor system 46 is a pump outlet channel 40C connected. Between the sensor 46 and the backflow channel 36 is a sample fluid return channel 40D connected. The channel 40D has a valve here 48 to open and close the channel 40D ,

As in 4 can be seen, a sample collection channel 40E be provided by the channels 40A . 40B . 40C and 40D connects to the lower sample module, the total at 52 you can see. The channel 40E leads to the adjustable throttle device 74 and to the sample chamber 56 for collecting a sample. The sample collection channel 40E has a chamber inlet valve here 58 for opening and closing the inlet into the sample chamber 56 , The sample chamber 56 can be a movable partition 72 for separating the sample fluid from a compressible fluid, such as air, to facilitate drawing of the sample, which is explained below. An outlet channel from the sample chamber 56 is also with a chamber outlet valve 62 provided, which can be a valve for manual operation. There is also a sample ejection valve 60 provided that can be a valve for manual operation. The channels from the valves 60 and 62 are provided with external channels (not shown) on the drill bit. The valves 62 and 60 allow removal of sample fluid when the work string 6 has been pulled out of the well once, which will be explained later.

If the packers 24 . 26 inflated, they seal against the wall of the borehole 4b , and as they expand further into a tight fit, the packers expand 24 . 26 something in the intermediate annulus 33 , If in the intermediate annulus 33 If fluid is trapped, this expansion can cause the pressure in the intermediate annulus 33 to a level above the pressure in the lower annulus 34 and the upper annulus 32 increase. For the operation of extendable elements such as the piston 45 , the pressure in the longitudinal bore 7 of the drill string 6 be higher than the pressure in the intermediate annulus 33 , That is why a Venturi pump is used 38 to build up excessive pressure in the intermediate annulus 33 to prevent.

The drill string 6 contains several return channels 36 for the drilling fluid, which is the return flow of drilling fluid from the lower annulus 34 to the upper annulus 33 allow if the packer 24 . 26 be expanded. At least on one of the return flow channels 36 is a venturi pump 38 provided with a structure designed to create a zone of lower pressure that can be used via the downward channel 41 and the purging control valve below 42 an excessive increase in pressure in the intermediate annulus 33 to prevent. Similarly, the Venturi pump could 38 with the low pressure duct 31 be connected so that from the venturi pump 38 generated low pressure zone could be used to the piston 45 or the packers 24 . 26 withdraw. Alternatively, as shown below using 7 another type of pump can be used for this purpose.

As in 2 several return flow channels can be provided. A backflow channel 36 is used to operate the Venturi pump 38 used. As in 3 and 4 can be seen has the backflow channel 36 an overall constant inner diameter until the venturi constriction 70 occurs. As in 5 is shown, the drilling fluid of the longitudinal bore 7 of the drill string 6 Pumped down, occurs near the bottom of the drill string on the drill bit 8th and is led back up into the annulus, which is indicated by the flow arrows. Assuming that the inflatable packer 24 . 26 are set and a seal on the borehole 4 has been reached, the ring flow through the return flow channel 36 diverted. When the flow of venturi narrowing 70 approaches, such a pressure drop occurs that the venturi effect in the venturi tube creates a low pressure zone. This low pressure zone is connected to the intermediate annulus 33 through the downward channel 41 , causing any build-up of excessive pressure in the intermediate annulus 33 is prevented.

The backflow channel 36 also contains an inlet valve 39 and an exhaust valve 80 for opening and closing the return flow channel 36 so the upper room 32 from the lower annulus 34 can be separated. The bypass channel 84 connects the longitudinal bore 7 of the work string 6 with the return flow channel 36 ,

In 6 Another possible embodiment of the present invention is shown, in which in the work line 6 a circulation valve 90 to open and close the inner hole 7 of the work string 6 is installed. There is also a cross valve 93 provided that in the cross channel 94 sits so that the current from the inner bore 7 of the work string 6 to the upper annulus 72 can reach. The rest of the configuration of the formation tester is the same as previously described.

The circulation valve 90 and the cross valve 92 are functionally the control system 100 assigned. For working the circulation valve 90 a drilling fluid pulse signal is transmitted down into the borehole, causing the control system 100 the position of the valve is signaled 90 to change. The same sequence would be required to the cross valve 92 to operate.

7 shows an alternative means of performing the functions performed by the venturi pump 38 be carried out. The centrifugal pump 53 can with its inlet to the downward channel 41 and to the low pressure duct 31 be connected. In the pump inlet channel to the intermediate annulus or piston are one downward discharge valve 57 and a sample inlet valve 59 intended. The pump inlet port is also with the low pressure side of the control valve 30 connected. This enables the pump to be used 53 or a similar pump for withdrawing fluid from the intermediate annulus 33 about the valve 57 to get a sample of the formation fluid directly from the formation through the valve 59 pull off or the cylinder 35 or the packers 24 . 26 pump out.

As in 8th shown, the use of a control system is part of the invention 100 for controlling the various valves and pumps and for receiving the output signal of the sensor system 46 , The tax system 100 is able to process the sensor information with the microprocessor / control device located in the borehole 102 to process and the data to the communication interface 104 to be delivered so that the processed data can be telemetrized to the surface using conventional technology. It should be noted that various forms of energy transmission can be used, for example drilling fluid pulse, acoustic, optical or electromagnetic energy. The communication interface 104 can be from a downhole electrical power source 106 be supplied. The power source 106 also supplies the flow line sensor system 46 , the microprocessor / control device 102 and the various valves and pumps.

Communication with the earth's surface can be done through the work string 6 in the form of pressure pulses and other devices as are known. In the case of drilling fluid pulse generation, the pressure pulse on the surface is via the two-way communication interface 108 receive. The data received in this way become the surface computer 110 transported for evaluation and display.

Through the communication interface 108 command signals can be sent down the fluid column where they are from the downhole communication interface 104 be received. The signals so received become the downhole microprocessor / controller 102 transported. The control device 102 then sends signals to the corresponding valves and pumps for their desired function.

The downhole microprocessor / controller 102 can also contain a preprogrammed sequence of steps based on predetermined criteria. Therefore, since well data such as pressure, resistivity, or dielectric constants are received, the microprocessor / controller automatically sends command signals through the controller to actuate the various valves and pumps.

The formation tester is for its function 16 located adjacent to a selected formation or storage layer. Next, a hydrostatic pressure is measured using the pressure sensor that is in the sensor system 46 the specific resistance of the drilling fluid at the formation is determined. This is achieved by having fluid in the sampling system 46 pumped, then the measurement of pressure and resistivity is interrupted. The data is processed in the borehole and then stored or transmitted upwards using the MWB telemetry system.

The operator then leaves the inflatable packers 24 . 26 expand and set. This is done by having the work strand 6 held stationary and the drilling fluid of the inner bore 7 down through the drill bit 8th and circulating up to the annulus. The valves 39 and 80 are open, which also means the return flow channel 36 is open. The control valve 30 is positioned so that the high pressure duct 27 aligned with the canal 28A . 28B for the inflation fluid and drilling fluid into the packer 24 . 26 can flow. Due to the pressure drop from the interior of the inner bore 7 out to the annulus across the drill bit 8th there is a significant pressure differential for the packers to expand 24 . 26 and for creating a good seal. The higher the throughput of the drilling fluid, the higher the pressure drop and the higher the expansion force that is applied to the packer 24 . 26 created. Alternatively or additionally, a further expandable element, for example the piston 45 , in contact with the wall of the borehole by suitably positioning the control valve 30 be extended.

The top packer element 24 can be wider than the lower packer element 26 be, which gives you more volume. This will make the bottom packer 26 set first. This can prevent fragments between the packers 24 . 26 be included.

The venturi pump 38 can then be used to build up excessive pressure in the intermediate annulus 33 prevent or the centrifugal pump 53 can be operated to remove the drilling fluid from the intermediate annulus 33 to remove. This is done by opening the downward drain valve 41 in the in 3 embodiment shown or by opening the valves 82 . 57 and 48 at the in 7 shown embodiment achieved.

When the fluid comes out of the intermediate annulus 33 is pumped out, the specific resistance and the dielectric constant of the fluid when withdrawn from the sensor system 46 are constantly monitored. The data measured in this way can be processed in the borehole and transmitted upwards in the borehole via the telemetry system. The resistivity and dielectric constant of the continuous fluid change from that of the drilling fluid to that of the drilling fluid filtrate and to that of the pristine formation fluid.

To perform formation pressure on construction and the pull-down tests, the operator closes the pump inlet valve 57 and the bypass valve 82 , This interrupts the emptying of the intermediate annulus 33 and enables immediate pressure build-up on the untouched formation pressure. The operator can choose to continue the recirculation to telemetrically transmit the print results uphole.

The operator can use the chamber inlet valve to take a sample of the formation fluid 58 open so the fluid in the channel 40E into the sample chamber 56 can occur. Because the sample chamber 56 is empty and there are atmospheric conditions, the partition wall 72 pressed down until the chamber 56 is filled. To regulate the flow into the chamber 56 is an adjustable throttle 74 intended. The purpose of the adjustable throttle 74 is to control the change in pressure across the packers when the sample chamber is open. If the throttle 74 would not exist, the packer seal could be lost due to the sudden change in pressure caused by opening the sample chamber inlet valve 58 is produced.

If the sample chamber 56 once filled, the valve can 58 be closed again, whereby a further pressure build-up is possible, which is monitored by the pressure sensor. If required, repeated pressure build-up tests can be performed by repeatedly pumping out the intermediate annulus 33 or by repeatedly filling additional sample chambers. The permeability of the formation can be calculated by later analyzing the pressure over the time data, for example using a known Horner diagram. In accordance with the teachings of the present invention, the data can of course also be analyzed before the packers 24 and 26 be emptied. In order to obtain a fixed, controlled, downward discharged volume, the sample chamber could 56 be used. The volume of fluid withdrawn can also be obtained from a downhole turbine meter located in the appropriate channel.

If the operator either wants to continue drilling or alternatively to check another storage layer, the packers can 24 . 26 emptied and withdrawn, causing the tester 16 returns to a standby mode. If a piston 45 used, it can be withdrawn. The packers 24 . 26 can be emptied by the control valve 30 is positioned so that the low pressure duct 31 with the inflation channel 28 flees. The piston 45 can be withdrawn by the control valve 30 is positioned so that the low pressure duct 31 with the cylinder channel 29 flees. The Venturi pump can be used to completely empty the packer or cylinder 38 or the centrifugal pump 53 be used.

If the sample chamber 56 Once on the surface, it can be off the work string 6 be separated. In order to empty the sample chamber, a container for holding the sample (which is still at formation pressure) is placed at the outlet of the chamber outlet valve 62 attached. On the squeeze valve 60 a source of compressed air is brought in. When opening the exhaust valve 62 the internal pressure is released, but the sample remains in the sample chamber. The one on the squeeze valve 60 The compressed air applied presses the partition 72 to the exhaust valve 62 , which removes the sample from the sample chamber 56 is pushed out. The sample chamber can be cleaned by passing it through the outlet valve with water or a solvent 62 filled and the partition 72 with compressed air via the ejection valve 60 is circulated. The fluid can then be analyzed for hydrocarbon number distribution, bubble pressure, or other properties.

If the operator decides to adjust the drilling fluid density, the method includes the steps of measuring the borehole hydrostatic pressure at the target formation. Then the packers 24 . 26 set so that an upper annulus 32 , a lower annulus 34 and an intermediate annulus 33 be formed within the borehole. Well fluid is then removed from the intermediate annulus 33 subtracted as previously described and the formation pressure in the intermediate annulus 33 measured. The other configurations of extendable elements can also be used to determine the formation pressure.

The method also includes the steps of adjusting the density of the drilling fluid according to the pressure readings of the formation so that the drilling fluid weight of the drilling fluid is very closely matched to the pressure gradient of the formation. This enables maximum drilling efficiency. After that, the inflatable packers 24 . 26 emptied, as previously explained, and drilling is resumed at the optimum density of the drilling fluid.

When the operator continues drilling to a second underground horizon and wants to perform another hydrostatic pressure measurement on the appropriate horizon, the packers 24 . 26 inflated and the intermediate annulus 33 , as previously stated, emptied. According to the pressure measurement, the density of the drilling fluid can be adjusted again, the inflatable packers 24 . 26 can be released from their seat and drilling of the borehole can be resumed at the exact overbalance.

The invention described here can also be used as a prevention device for blowing out close to the tool. If an underground bubble would occur, the operator would person the inflatable packer 24 . 26 put the valve 39 Bring it into the closed position and begin drilling fluid down the work string through the open valves 80 and 82 to circulate. When using blowout prevention, the pressure in the lower annulus can 34 by opening the valves 39 and 48 and by closing the valves 57 . 59 . 30 . 82 and 80 be monitored. The pressure in the upper annulus can be monitored while through the bypass valve by opening the valve 48 there is a direct circulation to the annulus. The pressure in the interior 7 The drill string can be monitored during normal drilling by both the inlet valve 39 as well as the exhaust valve 80 in the channel 36 closed and the bypass valve 82 be opened with all other valves closed. Eventually it would be the circulation channel 84 allow the operator to circulate fluid with greater density to control the "kick".

If the in 6 shown embodiment is used, the operator would alternatively the first and second inflatable packer 24 . 26 put and then the circulation valve 90 bring into the closed position. The inflatable packers 24 . 26 are placed at a position above the inflow zone so that the inflow zone is separated. That on the work string 6 included cross valve 92 is brought into the open position. Additives can then be added to the surface of the drilling fluid, increasing its density. The heavier drilling fluid is in the work string 6 down through the cross valve 92 circulated. Once the denser drilling fluid has replaced the lighter fluid, the inflatable packer can be seated 24 . 26 solved and the circulation valve 90 be brought into the open position. Drilling can then be resumed.

Although shown in detail herein and disclosed special invention fully capable of achieving the goals to achieve and those mentioned herein Of course, this disclosure merely provides advantages the illustration of the currently preferred configurations, so that no restrictions other than those are intended as described in the appended claims are.

Claims (17)

Device for checking a subsurface formation - with a work string ( 6 ), - with at least one on the work string ( 6 ) attached extendable element ( 24 . 26 . 45 ) that - to isolate a portion of the borehole ( 4 ) in the formation up to a sealing engagement with the wall of the borehole ( 4 ) is selectively extendable, and - to protect the extendable element ( 24 . 26 . 45 ) while using the work string ( 6 ) within the work line ( 6 ) is selectively retractable, - with an opening ( 51 ) in the work string containing an untouched formation fluid in the isolated portion of the borehole ( 4 ) can be suspended, - with one within the work line ( 6 ) arranged fluid transfer device ( 53 ) which is for a fluid connection to the opening ( 51 ) to transfer pristine formation fluid from the isolated portion of the borehole ( 4 ) can be connected, and - with a sensor ( 46 ) which is used to record at least one characteristic value of the fluid of the fluid transfer device ( 53 ) is functionally assigned, characterized by - a fluid flow path ( 28 ) within the work line ( 6 ) for selectively extending and retracting the at least one extendable element, at least one extendable element having at least one extendable packer ( 24 . 26 ), - a longitudinal bore ( 7 ) within the work line ( 6 ) to transport a pressurized drilling fluid down from the surface of the earth through the work string ( 6 ) for leaving the work line ( 6 ) near a lower end of the work string ( 6 ), the drilling fluid to the surface via a work string ( 6 ) surrounding annular space is returned, and - one within the work line ( 6 ) arranged return flow channel ( 36 ) for the drilling fluid, which has an inlet from the annular space under the at least one extendable packer ( 26 ) and an outlet to the annular space above the at least one extendable packer ( 24 ) having. Device according to claim 1, characterized in that - the at least one extendable element and the at least one extendable packer ( 24 . 26 ) and an extendable probe ( 45 ) and - that the fluid flow path - one with the at least one extendable packer ( 24 . 26 ) connected filling fluid channel ( 28 . 28a . 28b ) for selective filling and emptying of the at least one extendable packer ( 24 . 26 ), - one for selective extension and retraction of the probe ( 45 ) provided propellant fluid channel ( 29 ) with the probe ( 45 ) is functionally connected, - a high pressure duct ( 27 ) for a selective connection of the longitudinal bore ( 7 ) with the filling fluid channel ( 28 . 28a . 28b ) or with the Teibfluidkanal ( 29 ), - a low pressure duct ( 31 ) for a selective connection of the filling fluid channel ( 28 . 28a . 28b ) or the driving fluid channel ( 29 ) with the annulus and - a control device ( 30 ) within the work line ( 6 ) for the selective connection of the high pressure duct ( 27 ) with the filling fluid channel ( 28 . 28a . 28b ) or with the propellant fluid channel ( 29 ) and for the selective connection of the low pressure duct ( 31 ) With the filling fluid channel ( 28 . 28a . 28b ) or with the propellant fluid channel ( 29 ) having. Device according to claim 2, characterized in that the control device comprises a valve ( 30 ) having. Device according to one of claims 1 to 3, characterized by - a circulation valve ( 90 ), which is used to selectively stop the flow in the longitudinal bore ( 7 ) in this above the at least one extendable packer ( 24 . 26 ) is arranged, - a transverse channel ( 94 ) above the circulation valve ( 90 ), the longitudinal bore ( 7 ) and connecting the annulus, and - a cross valve ( 92 ) in the cross channel ( 94 ) to selectively allow drilling fluid flow from the longitudinal bore ( 7 ) to the annular space above the at least one extendable packer ( 24 . 26 ). Device according to one of claims 1 to 4, characterized in that - the fluid transfer device comprises a pump ( 53 ) has - that a bypass channel ( 84 ) within the work line ( 6 ) the longitudinal bore ( 7 ) with the return flow channel ( 36 ) connects - that a control device ( 82 ) in the work line ( 6 ) a flow through the bypass channel ( 84 ) selectively allowed, and - that to drive the pump ( 53 ) in the bypass channel ( 84 ) a pump drive device ( 55 ) is provided. Device according to claim 5, characterized in that the control device comprises a valve ( 82 ) having. Device according to one of claims 5 or 6, characterized in that the pump drive device comprises a turbine ( 55 ) having. Device according to one of claims 1 to 7, characterized by - a Venturi tube ( 38 . 70 ) in the return flow channel ( 36 ) and - a channel leading downwards ( 41 ) in the work line ( 6 ), the downward channel ( 41 ) to prevent overpressure in the insulated portion of the borehole ( 4 ) during the setting of the at least one extendable packer ( 24 . 26 ) an inlet in the isolated portion of the borehole ( 4 ) and an outlet at the constriction in the Venturi tube ( 38 . 70 ) having. Apparatus according to claim 8, characterized by - a within the downwardly leading channel ( 41 ) positioned first valve ( 42 ) to regulate the flow from the insulated portion of the borehole to the venturi ( 38 . 70 ), - one inside the return flow channel ( 36 ) positioned second valve ( 39 ) to regulate the backflow of the drilling fluid and - one of the first and the second valve ( 42 . 39 ) functionally assigned control system ( 100 ) for selective actuation of the first and second valve ( 42 . 39 ). Apparatus according to claim 9, characterized by - one in the work line ( 6 ) arranged sample chamber ( 56 ) used to collect a sample from the formation fluid in fluid flow communication with the fluid transfer device ( 53 ) stands and - a third valve ( 58 ) in the work line ( 6 ) to regulate the flow from the fluid transfer device ( 53 ) to the sample chamber ( 56 ), whereby for the selective actuation of the third valve ( 58 ) this the tax system ( 100 ) is functionally assigned. Device according to one of claims 1 to 10, characterized in that the sensor ( 46 ) has a resistivity sensor. Device according to one of claims 1 to 10, characterized in that the sensor ( 36 ) has a pressure sensor. Device according to one of claims 1 to 10, characterized in that the sensor ( 46 ) has a dielectric sensor. Procedure for testing a formation with a work string ( 6 ) in a borehole filled with a fluid ( 4 ), with the work string ( 6 ) at least one extendable element ( 24 . 26 ), an opening ( 51 ), a fluid transfer device ( 53 ) and a sensor ( 46 ), and the method comprises the steps: - extending the at least one extendable element ( 24 . 26 ) in sealing engagement with the wall of the borehole ( 4 ) to isolate a portion of the borehole ( 4 ) on the formation, - exposing the opening ( 51 ) the pristine formation fluid in the isolated portion of the pothole ( 4 ), - Extracting pristine formation fluid from the isolated portion of the borehole ( 4 ) through the opening ( 51 ) in the work line ( 6 ), - recording a characteristic value of the formation fluid and - withdrawing the at least one extendable element ( 24 . 26 ) in the work line ( 6 ) to protect the extendable element during further use of the work string ( 6 ), characterized in that the step of isolating the section of the Borehole ( 4 ) further extending and setting two of each other in the longitudinal direction of the work string ( 6 ) spaced packers ( 24 . 26 ), the at least one extensible element extending the annular space around the work strand ( 6 ) around in an upper annulus ( 32 ), a middle annulus ( 33 ) and a lower annulus ( 34 ) divided and - a fluid supply channel (longitudinal bore / 7 /) the work string ( 6 ) with the lower annulus ( 34 ) is connected, - a return flow channel ( 36 ) the lower annulus ( 34 ) with the upper annulus ( 32 ) connects, - a Venturi tube ( 70 ) in the return flow channel ( 36 ) is arranged and - between the middle annulus ( 33 ) and the Venturi tube ( 70 ) a channel leading downwards ( 31 ) is provided - that in the borehole through the fluid feed channel (longitudinal bore / 7 /) in the lower annulus ( 34 ) a fluid is circulated - that to form a low pressure zone on the Venturi tube ( 70 ) the fluid through the return flow channel ( 36 ) and through the Venturi tube ( 70 ) and - that the pressure in the middle annulus ( 33 ) by connecting the low pressure zone to the middle annulus ( 33 ) via the downward channel ( 41 ) is lowered. A method according to claim 14, characterized in that the step of fluid transfer further pumping pristine formation fluid from the wall of the borehole ( 4 ) to the sensor ( 46 ) with the help of a pump ( 53 ) which is in fluid flow connection with the opening ( 51 ) stands. A method according to claim 14 or 15, characterized in that the untouched formation fluid in a sample chamber ( 56 ) of the work string ( 6 ) is transferred. A method according to claim 16, characterized in that for filling the sample chamber ( 16 ) of the work string ( 6 ) the pristine formation fluid from the borehole wall ( 4 ) is pumped, the sample chamber ( 56 ) in a fluid flow connection with the opening ( 51 ) stands.